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Comparative Tests (comparative + test)
Selected AbstractsIndividual versus Household Migration Decision Rules: Gender and Marital Status Differences in Intentions to Migrate in South AfricaINTERNATIONAL MIGRATION, Issue 1 2009Bina Gubhaju This research tests the thesis that the neoclassical microeconomic and the new household economic theoretical assumptions on migration decision-making rules are segmented by gender, marital status, and time frame of intention to migrate. Comparative tests of both theories within the same study design are relatively rare. Utilizing data from the Causes of Migration in South Africa national migration survey, we analyse how individually held "own-future" versus alternative "household well-being" migration decision rules effect the intentions to migrate of male and female adults in South Africa. Results from the gender and marital status specific logistic regressions models show consistent support for the different gender-marital status decision rule thesis. Specifically, the "maximizing one's own future" neoclassical microeconomic theory proposition is more applicable for never married men and women, the "maximizing household income" proposition for married men with short-term migration intentions, and the "reduce household risk" proposition for longer time horizon migration intentions of married men and women. Results provide new evidence on the way household strategies and individual goals jointly affect intentions to move or stay. [source] Cross-contamination in the kitchen: effect of hygiene measuresJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2008A.E.I. De Jong Abstract Aims:, To determine the effect of hygiene measures on cross-contamination of Campylobacter jejuni at home and to select a safe tracer organism for C. jejuni. Methods and Results: Comparative tests were conducted with nonpathogenic Escherichia coli and Lactobacillus casei and L. casei was chosen as the safe tracer organism. Salads containing chicken breast fillet contaminated with a known number of C. jejuni and L. casei were prepared according to different cross-contamination scenarios and contamination levels of salads were determined. Cross-contamination could be strongly reduced when cleaning cutting board and cutlery with hot water (68°C), but generally was not prevented using consumer-style cleaning methods for hands and cutting board. Conclusions:, Dish-washing does not sufficiently prevent cross-contamination, thus different cutting boards for raw meat and other ingredients should be used and meat,hand contact should be avoided or hands should be thoroughly cleaned with soap. Lactobacillus casei can be used as a safe tracer organism for C. jejuni in consumer observational studies. Significance and Impact of the Study:, Cross-contamination plays an important role in the transmission of food-borne illness, especially for C. jejuni. This study delivers suitable data to quantitatively assess the risk of campylobacteriosis caused by cross-contamination and it shows the effect of different preventive hygiene measures. [source] Grain-Boundary Viscosity of Preoxidized and Nitrogen-Annealed Silicon CarbidesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2001Giuseppe Pezzotti Internal friction experiments were conducted on a model SiC polycrystal prepared from preoxidized (high-purity) SiC powder. This material contained high-purity SiO2 glass at grain boundaries in addition to a free-carbon phase, which was completely removed upon powder preoxidation. Comparative tests were conducted on a SiC polycrystal, obtained from the as-received SiC powder with the addition of 2.5 vol% of high-purity SiO2. This latter SiC material was also investigated after annealing at 1900°C for 3 h in a nitrogen atmosphere. Electron microscopy observations revealed a glass-wetted interface structure in SiC polycrystals prepared from both as-received and preoxidized powders. However, the former material also showed a large fraction of interfaces coated by turbostratic graphite. Upon high-temperature annealing in nitrogen, partial glass dewetting occurred, and voids were systematically observed at multigrain junctions. The actual presence of nitrogen could only be detected in a limited number of wetted interfaces. A common feature in the internal friction behavior of the preoxidized, SiO2 -added and nitrogen-annealed SiC was a relaxation peak that resulted from grain-boundary sliding. Frequency-shift analysis revealed markedly different characteristics for this peak: both the magnitude of the intergranular glass viscosity and the activation energy for grain-boundary viscous flow were much higher in the nitrogen-annealed material. Results of torsional creep tests were consistent with these findings, with nitrogen-annealed SiC being the most creep resistant among the tested materials. [source] Influence of cylinder-on-plate or block-on-ring sliding configurations on friction and wear of pure and filled engineering polymersLUBRICATION SCIENCE, Issue 2 2007P. Samyn Abstract Polyamides, polyesters and polyacetals are often used in line contacts under reciprocating or continuous sliding. These contacts are simulated on cylinder-on-plate (COP) or block-on-ring (BOR) tribotests. Comparative tests for pure, oil-filled and solid lubricated polymers at 100N and 0.3m/s are presented for relative material classification. Differences are discussed according to the sliding geometries. Thermal effects dominate friction and wear behaviour: the polymer glass transition temperature is exceeded in COP tests while the temperature is lower in BOR tests. Thick and brittle films are observed for pure polymers in BOR tests, promoting higher friction. The test configuration is mainly important for evaluation of internal lubricants. The efficiency of oil-lubricated polymers is not demonstrated in COP tests, while solid lubricants are not efficient in BOR tests. Deformation restricts the diffusion of oil lubricants in COP tests while solid lubricants are deposited on the polymer surface rather than being incorporated in the transfer film in BOR tests. Copyright © 2007 John Wiley & Sons, Ltd. [source] Orthodontic brackets removal under shear and tensile bond strength resistance tests , a comparative test between light sourcesLASER PHYSICS LETTERS, Issue 3 2008P.C.G. Silva Abstract We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 ± 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Qualitative aspects of sperm stock in males and females from Eupelmus orientalis and Dinarmus basalis (Hymenoptera: Chalcidoidea) as revealed by dual fluorescencePHYSIOLOGICAL ENTOMOLOGY, Issue 2 2002David Damiens Abstract The quality of a sperm population can be characterized physiologically and its fecundity predicted by its viable : non-viable sperm ratio. To improve the knowledge of reproductive strategies in two ectoparasitoid hymenopteran species, Eupelmus orientalis Crawford (Hymenoptera: Eupelmidae) and Dinarmus basalis Rondani (Hymenoptera: Pteromalidae), the assessment of sperm viability using the dual fluorescence staining procedure SYBR-14 : propidium iodide was developed. The aim of the study was to provide a comparative test in vitro applicable to both sexes to study the evolution of sperm quality at various stages of the reproductive processes. The reliability of propidium iodide to detect non-viable sperm (stained in red) was confirmed in both species on the basis of two stress tests (ethanol and Triton X-100) but our study also revealed that propidium iodide concentrations must be adequately adjusted for each single species. This experiment also demonstrated the physiological heterogeneity of sperm populations in E. orientalis and D. basalis males and females. In both species, 40% of the sperm in the seminal vesicles was found to be non-viable. By contrast with E. orientalis, the populations of non-viable sperm estimated from the seminal vesicles of D. basalis were found to be strongly different from those observed in the spermatheca. From the present results, the population of viable sperm detected in the spermatheca of females from both species proved a reliable predictor of fertilization achieved in ovipositing females. [source] ARE PINNIPEDS FUNCTIONALLY DIFFERENT FROM FISSIPED CARNIVORES?EVOLUTION, Issue 3 2000THE IMPORTANCE OF PHYLOGENETIC COMPARATIVE ANALYSES Abstract., It is widely assumed that adaptations to an aquatic lifestyle are so profound as to produce only obvious differences between pinnipeds and the remaining, largely terrestrial carnivore species ("fissipeds"). Thus, comparative studies of the order Carnivora routinely examine these groups independently. This approach is invalid for two reasons. First, fissipeds are a paraphyletic assemblage, which raises the general issue of when it is appropriate to ignore monophyly as a criterion for inclusion in comparative studies. Second, the claim that most functional characters (beyond a few undoubted characteristic features) are different in pinnipeds and fissipeds has never been quantitatively examined, nor with phylogenetic comparative methods. We test for possible differences between these two groups in relation to 20 morphological, life-history, physiological, and ecological variables. Comparisons employed the method of independent contrasts based on a complete and dated species-level phylogeny of the extant Carnivora. Pinnipeds differ from fissipeds only through evolutionary grade shifts in a limited number of life-history traits: litter weight (vs. gestation length), birth weight, and age of eyes opening (both vs. size). Otherwise, pinnipeds display the same rate of evolution as phylogenetically equivalent fissiped taxa for all variables. Overall functional differences between pinnipeds and fissipeds appear to have been overstated and may be no greater than those among major fissiped groups. Recognition of this fact should lead to a more complete understanding of carnivore biology as a whole through more unified comparative tests. Comparative studies that do not include monophyletic groups for phylogenetically based comparative tests should be reconsidered. [source] RAPA: a novel in vitro method to evaluate anti-bacterial skin cleansing productsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010S. A. Ansari Synopsis Development of efficacious anti-bacterial skin cleansing products has been limited by the availability of a pre-clinical (in vitro) method to predict clinical efficacy adequately. We report a simple and rapid method, designated as rapid agar plate assay (RAPA), that uses the bacteriological agar surface as a surrogate substrate for skin and combines elements of two widely used in vivo (clinical) methods (Agar Patch and Cup Scrub). To simulate the washing of the human hand or forearm skin with the test product, trypticase soy agar plates were directly washed with the test product and rinsed under running tap water. After air-drying the washed plates, test bacteria (Staphylococcus aureus or Escherichia coli) were applied and the plates were incubated at 37°C for 18,24 h. Using S. aureus as the test organism, anti-bacterial bar soap containing triclocarbanilide showed a strong linear relationship (R2 = 0.97) between bacterial dose and their per cent reduction. A similar dose-response relationship (R2 = 0.96) was observed for anti-bacterial liquid hand soap against E. coli. RAPA was able to distinguish between anti-bacterial products based on the nature and level of actives in them. In limited comparative tests, results obtained by RAPA were comparable with the results obtained by clinical agar patch and clinical cup scrub methods. In conclusion, RAPA provides a simple, rugged and reproducible in vitro method for testing the relative efficacy of anti-bacterial skin cleansing products with a likelihood of comparable clinical efficacy. Further testing is warranted to improve the clinical predictability of this method. Résumé Le développement des produits de nettoyage de peau antibactérienne efficace a été limité par la disponibilité d'une méthode (in vitro) préclinique pour prévoir en juste proportion l'efficacité clinique. Nous rapportons une méthode simple et rapide, indiquée comme analyse rapide de plat d'agar (RAPA) ce des utilisations la surface bactériologique d'agar comme substrat de remplacement pour la peau et combinons des éléments de deux méthodes (cliniques) in vivo employées couramment (correction d'agar et la tasse frottent). Pour simuler le lavage de la peau humaine de main ou d'avant-bras avec le produit d'essai, des plats de l'agar de soja de trypticase ont été directement lavés avec le produit d'essai et rincés sous l'eau du robinet courante. Après l'air séchant les plats lavés, les bactéries d'essai (S. doré Ou Escherichia coli) étaient appliquées et des plats ont été incubées au °C 37 pendant 18,24 heures. Utilisant S. doré Comme organization d'essai, le triclocarbanilide contenant du savon de barre antibactérienne a montré un rapport linéaire fort (R2 = 0.97) entre la dose bactérienne et leur réduction de pour cent. On a observé un rapport semblable de réponse à dose donnée (R2 = 0.96) pour le savon liquide antibactérien de main contre E. coli. RAPA pouvait distinguer les produits antibactériens basés sur la nature et le niveau des actives dans eux. Dans les essais comparatifs limités, résultats obtenus par RAPA étaient comparables aux résultats obtenus par la correction clinique d'agar et la tasse clinique frottent des méthodes, en conclusion, RAPA fournit à une méthode in vitro simple, raboteuse et reproductible pour examiner l'efficacité relative des produits de nettoyage de peau antibactérienne la probabilité de l'efficacité clinique comparable. Davantage d'essai est justifié pour améliorer la prévisibilité clinique de cette méthode. [source] | ||||||||||